Ce对Al-Zn-Mg-Cu-Sc合金组织和力学性能的影响

为了研究Ce元素对T6态Al-7.5Zn-2Mg-2.3Cu-0.1Sc合金显微组织和力学性能的影响,通过改变合金中Ce元素的添加量,采用光学显微镜、扫描电子显微镜和电子万能实验机对合金的显微组织、拉伸断口形貌和力学性能进行了研究.结果表明,加入质量分数为0.2%的Ce元素可以显著细化Al-7.5Zn-2Mg-2.3Cu-0.1Sc合金的铸态和T6态显微组织.在合金的T6处理过程中随着时效时间的增加,合金硬度和抗拉强度均先增加后降低,合金的硬度和抗拉强度峰值分别为216 HB和681.7 MPa,合金最高屈服强度为638.2 MPa.合金拉伸断口呈韧脆混合断裂特征.

Effect of Ce on microstructure and machanical properties of Al-Zn-Mg-Cu-Sc alloy

In order to study the effect of Ce element on both microstructure and mechanical properties of T6 treated Al-7.5Zn-2Mg-2.3Cu-0.1Sc alloy, the addition amount of Ce element in the alloy was changed, and the microstructure, morphologies of tensile fracture surfaces and mechanical properties of the alloy were investigated with the optical microscope, scanning electron microscope(SEM)and electronic universal testing machine. The results show that after adding the Ce element with the mass fraction of 0.2%, the microstructures of the alloy with as-cast and T6 treated states can be obviously refined. In the T6 treatment process of the alloy, the hardness and ultimate tensile strength of the alloy firstly increase and then decrease with increasing the aging time. In addition, the peak hardness and ultimate tensile strength of the alloy are 216 HB and 681.7 MPa, and the maximum yield strength is 638.2 MPa. The tensile fracture surfaces of the alloy show the mixed ductile-brittle fracture feature.